The present invention relates generally to systems and methods for analysis of fluid systems using a probe, and more particularly to system and method for optically sampling and analysis of liquid systems using a fiber optic probe having particularly utility for in situ environmental monitoring.
Existing systems and methods for the measurement of pollutants in wells, aquifers and other environmental systems, are slow and cumbersome and substantially limited in their utility for in situ monitoring, and are limited in the ability to allow for turbidity, and other background interferences.
The invention solves or substantially reduces in critical importance problems with existing environmental monitoring systems by providing a fiber optic sensor probe which transmits tunable ultraviolet light to a remote monitoring location to permit quantitative measurements of an aqueous sample. The probe includes an optical fiber terminating in a sampling structure at the distal end of the probe which is inserted into the liquid to be analyzed, a selected excitation light beam is transmitted to the sample region through the fiber, and the resulting fluorescence characteristic of the liquid is transmitted back through the fiber structure to an optical detector. The sampling region at the end of the probe is configured to absorb or reflect away all excess excitation light so that only the resulting characteristic fluorescence is transmitted back to the detector, and may have a microporous base to exclude solid particles from the sampling region. The structure of the probe eliminates undesirable backscatter of light into the detector, has a fixed optical path length which allows turbidity corrections to be made, and is sufficiently compact to be used in model aquifer studies without significantly perturbing the aqueous flow. The invention may find particularly utility in the analysis of aromatic hydrocarbons via laser-induced fluorescence or Raman spectroscopy.
For the purpose of describing the invention and defining the scope thereof, the term "optical" shall, in accordance with customary usage, be defined herein to include only ultraviolet, visible, near infrared, mid-infrared and far infrared regions of the electromagnetic spectrum lying in the range of about 0.1 to about 1000 microns (see e.g., Garbuny, Optical Physics, Academic Press, NY (1965) pp 1-6), and more specifically the range from about 0.2 micron, the approximate lower limit of operation of fine quality quartz, to about 50 microns, the approximate upper limit of operation of long wavelength transmitting materials.
It is therefore a principal object of the invention to provide system and method for environmental monitoring.
It is another object of the invention to provide system and method for analysis of fluid systems using a probe.
It is another object of the invention to provide a portable system for on-site environmental monitoring of liquid systems such as a deep well, aquifer, lake or the like.
It is another object of the invention to provide a fiber optic probe for use in analysis of liquid systems such as a deep well or aquifer.
It is a further object of the invention to provide system and method for in situ qualitative and quantitative analysis of remote liquid systems such as a deep well or aquifer.
These and other objects of the invention will become apparent as a detailed description of representative embodiments proceeds.